A beautiful example of the famous eurypterid—and state fossil of New York—Eurypterus remipes, on display at Ithaca's Paleontological Research Institution and its Museum of the Earth.
Paleontological Research Institution and its Museum of the Earth (Ithaca, New York)
The Paleontological Research Institution (PRI) and its Museum of the Earth in Ithaca, New York, maintains one of the most comprehensive Paleozoic invertebrate collections in the United States. Eurypterids—the centerpiece fossil of the 2013 National Fossil Day artwork—are an important part of that collection. Eurypterids were shaped like a lobster but they were only distantly related. Some of them measured more than eight feet long! They existed in the shallow seas that covered large parts of what are now eastern North America and western Europe during the Paleozoic Era. They also lived in fresh water environments. These armored beasts inhabited the planet for more than 200 million years, from the earliest Ordovician Period to the middle of the Permian Period.
The monster described above was the largest of eurypterids. Most eurypterids, however, were much smaller, less than two feet in length. Most were probably predatory, capturing prey with their claws, but some lack large grasping claws and may have been scavengers or fed on small prey on the bottom. Although they were primarily aquatic (living in both marine and fresh water settings), some forms may have been semi-terrestrial, perhaps in swamps or tidal flats.
Like all arthropods, they had an exoskeleton made of chitin, but unlike many (for example, many crabs, lobsters, and the extinct trilobites), this exoskeleton was not mineralized, which might help explain why fossil eurypterids are so uncommon. Indeed, eurypterids are relatively rare fossils, and not very diverse. There are about 60 described genera encompassing around 300 species. Compare that to the trilobite record of thousands of genera encompassing more than 17,000 species. Most eurypterid species are based on only a small number of specimens, many only by a single fossil, and these specimens are usually fragmentary or incomplete.
This map shows eurypterid fossil discoveries in the northeastern United States. Upstate New York is home to most of them. The green star shows the location of PRI and its Museum of the Earth in Ithaca. Map developed from Paleobiology Database data and map viewer.
Rare elsewhere, New York is prime hunting grounds for eurypterid fossils. The very first eurypterid fossils were discovered there in 1818 and described by the New York Geological Survey. More eurypterids have been described from the rocks of New York State than from anywhere else in the world. By far the most common eurypterids in North American museum and teaching collections come from Silurian Bertie "Waterlime" Formation of upstate New York. The PRI Museum of the Earth is home to many of these eurypterid fossils, including the world's largest complete specimen of a eurypterid, measuring 49.5 inches (more than 4 feet) long. Recognizing the significance of eurypterids to New York, in 1984 the State legislature honored what is likely the most common species in the state—Eurypterus remipes—as the official state fossil.
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2013 Paleozoic Partner feature articles: | January: Fossils of the 2013 National Fossil Day Artwork | February: Paleontological Research Institution, Museum of the Earth | March: Falls of the Ohio State Park | April: Field Museum of Natural History, Mazon Creek Collection | May: Prehistoric Trackways National Monument |